Nine hundred sixty (960) participants will be randomized into 2 groups, in a 2:1 ratio, to receive the inactivated Coronavac/Butantan vaccine (VACC, N=640) and a group to receive the immunizing BNT162b2 (Pfizer) (BNTC, N=320). The VACC group will also be compared to a group of adults aged 18 to 49 who received Coronavac (ADU, N=160). The main outcome will be the geometric title of neutralizing antibodies and the secondary outcomes will be the incidence of the number of cases confirmed by RT-PCR, the cellular immune response and frequency of adverse events. Outcomes will be evaluated before the first dose, and 28 and 90 days after the second dose, and followup after 6 and 12 months. The study hypothesis is that the cellular and humoral immune response of children and adolescents is not inferior to the age group 18 to 49 years, who received Coronavac and compared to children vaccinated with the immunizing BNT162b2 (Pfizer) and that the inactivated vaccine presents lower reactogenicity for the age group studied.
